Effects of molecular-transport coefficients on the rate of turbulent combustion

Karpov, V. P.; Severin, E. S.

doi:10.1007/bf00756242

Cited by 85 publications

(47 citation statements)

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“…In particular, as shown by Lipatnikov and Chomiak [56], the three most extensive experimental databases obtained from expanding statistically spherical premixed flames [66][67][68] are reasonably well fitted with S T ∝ U Ka −1/3 or S T ∝ U Da 1/4 and, therefore, indicate a less pronounced dependence of S T /U on Ka or Da when compared to the present DNS. Differences between these measured data and the present DNS results could be attributed to a number of factors, such as (i) thermal expansion effects, reviewed elsewhere [69,70], (ii) differences between experimental and numerical flame configurations, (iii) differences between methods adopted to evaluate S T in the experiments and simulations [71], etc.…”

Section: Turbulent Wave Speedsupporting

confidence: 78%

Direct numerical simulation study of statistically stationary propagation of a reaction wave in homogeneous turbulence

Lipatnikov

2017

Phys. Rev. E

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A three-dimensional (3D) direct numerical simulation (DNS) study of the propagation of a reaction wave in forced, constant-density, statistically stationary, homogeneous, isotropic turbulence is performed by solving Navier-Stokes and reaction-diffusion equations at various (from 0.5 to 10) ratios of the rms turbulent velocity U to the laminar wave speed, various (from 2.1 to 12.5) ratios of an integral length scale of the turbulence to the laminar wave thickness, and two Zeldovich numbers Ze = 6.0 and 17.1. Accordingly, the Damköhler and Karlovitz numbers are varied from 0.2 to 25.1 and from 0.4 to 36.2, respectively. Contrary to an earlier DNS study of self-propagation of an infinitely thin front in statistically the same turbulence, the bending of dependencies of the mean wave speed on U is simulated in the case of a nonzero thickness of the local reaction wave. The bending effect is argued to be controlled by inefficiency of the smallest scale turbulent eddies in wrinkling the reaction-zone surface, because such small-scale wrinkles are rapidly smoothed out by molecular transport within the local reaction wave.

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Section: Turbulent Wave Speedsupporting

confidence: 78%

Direct numerical simulation study of statistically stationary propagation of a reaction wave in homogeneous turbulence

Lipatnikov

2017

Phys. Rev. E

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“…(a) The Moscow database [36], with measurements performed in a fan stirred bomb. The line represents a reduced dataset selected by Lipatnikov and Chomiak [35], limited to moderate turbulence and Le ≈ 1.…”

Section: As a Results The Uncertainty In Measurements Ofmentioning

confidence: 99%

Turbulent burning rates of methane and methane–hydrogen mixtures

Fairweather

Ormsby

Sheppard

et al. 2009

Combustion and Flame

113

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“…18 It is worth noting here that alternative methods of assigning a characteristic Lewis number have been proposed based on heat release measurements 30,31 and mole fractions of the mixture constituents. 32 In the past, the significant effects of characteristic Lewis number Le on various aspects of premixed combustion (e.g., thermo-diffusive instability of laminar flames, burning rate, scalar gradient statistics, and combustion modelling) have been addressed analytically, [33][34][35][36] experimentally, [37][38][39][40][41][42][43] and numerically. 18,[44][45][46][47][48][49][50][51][52][53] Various concepts, which have been developed in order to explain such effects in turbulent flames, are reviewed elsewhere.…”

Section: Introductionmentioning

confidence: 99%

Effects of Lewis number on vorticity and enstrophy transport in turbulent premixed flames

2016

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The effects of Lewis number Le on both vorticity and enstrophy transport within the flame brush have been analysed using direct numerical simulation data of freely propagating statistically planar turbulent premixed flames, representing the thin reaction zone regime of premixed turbulent combustion. In the simulations, Le was ranged from 0.34 to 1.2 by keeping the laminar flame speed, thermal thickness, Damköhler, Karlovitz, and Reynolds numbers unchanged. The enstrophy has been shown to decay significantly from the unburned to the burned gas side of the flame brush in the Le ≈ 1.0 flames. However, a considerable amount of enstrophy generation within the flame brush has been observed for the Le = 0.34 case and a similar qualitative behaviour has been observed in a much smaller extent for the Le = 0.6 case. The vorticity components have been shown to exhibit anisotropic behaviour within the flame brush, and the extent of anisotropy increases with decreasing Le. The baroclinic torque term has been shown to be principally responsible for this anisotropic behaviour. The vortex stretching and viscous dissipation terms have been found to be the leading order contributors to the enstrophy transport for all cases, but the baroclinic torque and the sink term due to dilatation play increasingly important role for flames with decreasing Le. Furthermore, the correlation between the fluctuations of enstrophy and dilatation rate has been shown to play an important role in determining the material derivative of enstrophy based on the mean flow in the case of a low Le.

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Effects of molecular-transport coefficients on the rate of turbulent combustion

Cited by 85 publications

References 0 publications

Direct numerical simulation study of statistically stationary propagation of a reaction wave in homogeneous turbulence

Direct numerical simulation study of statistically stationary propagation of a reaction wave in homogeneous turbulence

Turbulent burning rates of methane and methane–hydrogen mixtures

Effects of Lewis number on vorticity and enstrophy transport in turbulent premixed flames

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